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1-10 of 13 messages
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Ameritron causes computer to reboot at switch on
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by WB9TEV on December 26, 2004
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I own a Ameritron 811H. It really does very well giving me full rated output and very good reports.
Here is the question/problem.. I do have what I consider low AC line voltage. I have monitored my line voltage and see anywhere from 120 volts peak during the night to a more normal 114 volts some times less. When I turn on the AMP I do get a quick small drop of between 111 to 12 volts AC but it recovers tot he average at the time very quickly. I see this drop while talking on the AMP
On the AMP HV I see a normal of 1700 maybe slightly higher to 1725. On transmit I see a drop to 1450 volts or so on voice peaks. All of this from what I have read is normal for the AMP. I do have the transformer tapped at 110 volts lowering it from the factory 120 volts as when I first got the amp the HV numbers were about 100 to 120 volts less.
The question I have is could these lower voltages be the cause of a problem I have on my computer (on same cricuit) sometimes it will start rebooting when I switch the AMP on. I do as I said have a quick voltage drop when the amp is first switched on and seems if the numbers are on the lower side that is too much for the computer and is reboots itself. however, after AMP is on and even while tuning it or using it the computer is happy and works fine. also. it does NOT always reboot again maybe related to low voltage at the time
One last item. I did blow a fuse on the amp the other day when I switched the AMP on. I replaced that fuse and all is fine might not be related but a friend said he thought the fuse blowing could also be caused or related to low AC line voltage as at the time of switching on the amp the transformer in the AMP draws more current for a seccond ot two since the voltage might go low causing the amp to try to drop more current .
Again, the weird thing is the AMP tunes great works great and seems to otherwise be just fine. It seems that the initial kick of the switching on the amp the other equipment on the circuit are just not happy. I do have a seond computer on same circuit and a small refrig. I have had both computers do a reboot at AMP switch on... I have also had them both do nothing when it is switched on
repeating one other item after the AMP is on all equipment seems to be fine even when I tune the amp the computers run great..
Would an isolation transformer or line conditioner right ahead of the AMP be the fix here? if so any suggested brands rating etc.. Any ideas??
Thanks
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RE: Ameritron causes computer to reboot at switch
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by W2LO on December 26, 2004
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A refrigerator, and two computers are on the same line as the amp. That line is severely overloaded. The amp should be running on a dedicated 220v line all by itself.
Mike W2LO
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RE: Ameritron causes computer to reboot at switch
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by K8AC on December 26, 2004
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It's not clear from your description just what all is connected to this 120 volt circuit. If you have the amp and multiple computers and the small fridge, it is almost certainly overloaded. It is either a 15 or 20 amp circuit and I'll bet if you add up the current draws of all devices on the circuit that you are at the limit. There are several things you could do:
1. Run a new 240V line for the amp.
or
2. Run a separate 120 volt line (20 amps) just for the amp
and
3. Isolate the computer from the line with a UPS (such as one by APC)
For measuring power consumed by the devices on the line: Home Depot is selling a nice little device called the Model P4400 Kill A Watt. It plugs into a wall socket and you plug the device being measured into it. It has a digital display that can read line voltage, amps drawn, power consumed in watts, volt-amperes power factor, line frequency, killowatt hours.
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RE: Ameritron causes computer to reboot at switch
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by WB9TEV on December 26, 2004
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kinda what i figured. The Kill A watt meter sounds interesting for many reasoms I did a search of the home depot site and can not locate it do you
have a url to their web site for it
thanks
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RE: Ameritron causes computer to reboot at switch
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by W0FEN on December 26, 2004
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All the answers are correct so far. What is not said is that is 220 Vac available? If yes, then by all means use that route. If not, and the voltage coming into the panel is this low, then the choices are limited. First off complain to the utility company. Most state PUC (or other) regulate what voltage can be delivered to a customer. If you have had to replace any appliances that use motors (refrigerators, furnaces, AC) then the utility voltage is suspect. As a last recourse, you might try a ferro-resonnant transformer to regulate the voltage going to the computer. The brand name of SOLA comes to mind. It will also remove ANY spikes, low voltages (brownouts), or surges (high voltages). Sola transformers are not cheap but sometimes at hamfests they can be bought cheaply. Any amp (even not full-powered ones) should be run on 220 Vac if available.
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RE: Ameritron causes computer to reboot at switch
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by KB1LKR on December 27, 2004
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Actually it's 240V not 220V in the USA/Canada (2*120V), unless you take your service at 120/208V 3phase wye -- common for commercial service, *very* unusual for residential [note 208=120*sqrt(3) same ratio as 277/480V where 277 is used for non incandesent lighting loads to save copper costs], but I digress. You should always expect the line voltage to be within +10%/-15% (102 - 132V or 204-264V) and in normal circumstances (e.g. not during severe summer heatwaves in the early evening) +/-5% or so of nominal at your service entrance (114-126V or 228-252V). If you are lower your utility may have a problem or may need to change a transformer tap.
Retapping the Amp for 110V vs 120V will raise all the secondary voltages about 9%, beware particularly of the PA tube filiment voltages running too high! It won't do anything for the tranient voltage drop the computer may be seeing though.
In any case 240V would be superior to 120V as the voltage drop on the wiring will be half, and either one requires only 2 wires (+ grounding conductor) so wire cost is nominally identical. I say nominaly, for while a 12AWG 20A/240V circuit would be fine (there is NO value in running a 15A 240V circuit vs 20A even though it would probably sufice), you might, if the run is long want to use *larger* than 12AWG for a *dedicated* 20A/120V circuit, e.g. 10AWG, to reduce the drop.
If the circuit is truely awkward to have run you might (assuming only the computer and the amp and some incidential loads (e.g desklamp) are on the circuit) you might look at a UPS for the computer and/or a new computer PS as it may have problems. I would NOT run even a small bar/dorm room sized 'frig on the circuit, the second computer may be alright though it is still another couple hundred watts at somthing less than unity power factor (measure AC voltage and current it's the VA's that matters not the real power (watts) because even the *reactive* current causes voltage drop, though it does no work and you are not paying for it (at least residentially -- commercially they often ding you for low power factor and for peak demand in addition to kW-hrs used).
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RE: Ameritron causes computer to reboot at switch
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by WB9TEV on December 28, 2004
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Little update..
I wanted to perform a test to see how much voltage I could get to the shack and how steady.. Went to the local hardware store picked up 100 feet of 10/3 with grd. got a new 20 amp breaker long story short all of my problems seems to of gone away. I plugged the amp into the temp drop of the 10/3.. I monitored the voltage stays at 120.8 to 121.3 so abt 1/2 volt.
this AC is about 5 to 7 volts higher then the wall plug AC. switched on the amp and man was it quite. nothing thumped and computers or anything else did not even a flinch..
sooo will make a separate run in attic to the shack.. seems the experiment proves the voltage drop thru the house is NOT typical of what the entrance panel sees...
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RE: Ameritron causes computer to reboot at switch
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by WA9SVD on December 30, 2004
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Considering the voltage drop you have at the wall socket, I'd be concerned that the wiring (at least to that wall socket) is inadequate even without the amp connected to that circuit.
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RE: Ameritron causes computer to reboot at switch
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by WB9TEV on December 30, 2004
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ok could someone help me again. I took the suggestions above.. wired the shack for 240 volt.. then switched the plug on the 811H amp and chnaged the wiring taps for 240 the Ameritron manal says to simple cut off the plug add a 240 plug and change the trasnformer taps. Could someone please take a look at the page 4 of the manual I have left the connection between the F and E removed between D & C moved the connection to A to 1 and B to 2 .. looks fine yet when I fire up the amp it blows the two 8 AMP fuses in line both of them nothign else seems o happen the HV starts up scale get a few hunderd the the fuses let go. i do not thikn I have harmed the AMP yet BUT thought i woudl get some expert advise before I do <g>.. the manual says to replace the 120 volt plug with the 240 and yet says to make sure the green wire goes to the grd lug of the plug. yet the other two the white and black going to each of the 120 legs in the 220 line.. (in line coming form the amp is black white and green..
any ideas>>??
thanks
Dan
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RE: Ameritron causes computer to reboot at switch
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by W0FEN on December 31, 2004
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I downloaded the manual.
The connections you need are:
A to 1
B to 2
D to E
Previous connections that are open:
E to F
C to D
This should do it.
Good luck. 240 Vac will provide much stiffer high voltage.
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